If you can get legit value for the guy I'd cut bait. I do not see a player anywhere near ready for NHL action. There's little room in the NHL for small offensive defencemen who are highly suspect defensively. His OHL production is a bit of an enigma (possibly injury related) but I hate to see a players point-per-game production drop in three consecutive junior campaigns (although he did light it up in the playoffs last year).
Give him 2-3 years in the AHL and we'll know if he can really hack it with the big boys...until then I'm calling him a long term project with decent to good upside.
Look at it this way, Ryan Ellis was drafted two years before Murphy, is a better player and has still only played 32 NHL games.